Add a check for (struct sigaction).sa_sigaction as it's not present on all architectures.

Signed-off-by: Garrett Cooper <yanegomi@gmail.com>
diff --git a/configure.ac b/configure.ac
index 4b98a42..899d03e 100644
--- a/configure.ac
+++ b/configure.ac
@@ -61,6 +61,7 @@
 LTP_CHECK_CRYPTO
 LTP_CHECK_LINUX_PTRACE
 LTP_CHECK_SELINUX
+LTP_CHECK_SIGNAL
 LTP_CHECK_SYSCALL_EVENTFD
 LTP_CHECK_SYSCALL_MODIFY_LDT
 LTP_CHECK_SYSCALL_NUMA